FISH analysis of the chromosomal status of spermatozoa from three men with45,XY,der(13;14)(q10;q10) karyotype

Meiotic segregation of chromosomes 13 and 14 was studied in the ejaculated spermatozoa of three men carrying a translocation der(13;14)(q10;q10). The spermatozoa of these patients and of a donor with a normal 46,XY karyotype (control) were analysed by two-colour fluorescent in-situ hybridization (FI SH) with specific chromosomal painting of chromosomes 13 and 14, by two-col our FISH detecting chromosomes 18 and 21 and by triple-colour FISH for chro mosomes X, Y and 8, For patients 1, 2 and 3, respectively, 81.34, 82.60 and 88.90% of the analysed nuclei showed normal or balanced chromosomal status , resulting from the alternate segregation of the translocation, The rates of spermatozoa with an unbalanced status (disomy and nullisomy, 13 or 14) r esulting from the adjacent mode of segregation were estimated respectively at 18.06, 16.32 and 10.80 (for patients 1, 2 and 3), Additional colour FISH analysis with probes specific for chromosomes X, Y, 8, 18 and 21 showed a significant increase in some disomy frequencies (8, 18, 21, X and Y for pat ient 1, only 18 for patient 2) in comparison with the control. These result s would seem to indicate an interchromosomal effect.